Based on the folded transformation optics, a methodical approach for manipulating the orientation and directivity of a planar antenna beam is propounded. Unlike the classical phased array antennas, the tilted emitting beam is achieved by a homogeneous metamaterial-based superstrate in a triangle shape configuration, rather than by utilizing complicated and bulky phase shifters. Such a simple coating layer is elaborately designed via folding the virtual space to physical one with an affine transformation. The competency of the proposed method is demonstrated through some examples, indicating the capability of the coating layer in tilting the radiated beam to any desired off-normal directions in both the upper and lower half spaces. To authenticate the concept, a tilted beam metamaterial-based antenna is fabricated and tested; it is observed that the experimental results are in a good agreement with the numerical simulations and theoretical predictions. The presented method paves the way towards steering the beam of a metamaterial-assisted antenna, which has been a topic of great interest in several fields of engineering, such as antenna technologies, satellite communication, and multiple-input multiple-output systems.

The wall-effect compensation is one of the most annoying steps in modern through wall imaging (TWI) problems. Presence of wall not only increases the computational burden due to clutter rejection and complex imaging algorithms, but also blurs the reconstructed image. To mitigate this drawback, different wall-clutter rejection methods have been subject of numerous researches in recent years. However, these wall-clutter rejection methods mainly focus on removing the first strong reflection of wall. In this study, a novel wall-removal method (not only wall-clutter rejection) based on transformation optics (TO) is addressed. This is the first time that TO has been applied to TWI problem. Using this new method, TWI is cast to a free space imaging problem which is computationally more effective and results in more focused images. Real-time imaging is also more available in this case. Without loss of generality, a two-dimensional TWI configuration is assumed to evaluate the provided technique. A single point-like scatterer hidden behind a wall is used to obtain the imaging system point spread function resulted by the proposed technique. Finally, it is shown that the presented method is valid even for lossy walls. Reconstructed images show satisfactory focusing that highlight the capabilities of presented method.

Based on the transformation acoustic (TA) methodology, an innovative approach for designing arbitrary shape concentrators is proposed. Unlike previous works, which utilized inhomogeneous and anisotropic materials to localize the incident acoustic waves in an arbitrary domain, the same functionality will be attained by introducing only one homogeneous anisotropic medium, which is called Acoustic nihility media (ANM). A great advantage of this method is that the attained materials are not dependent on the shape of the concentrator. That is regardless of the device geometry, a constant ANM will be used for each new shape and the output results do not alter. This will circumvent the conventional transformation acoustics' sophisticated and tedious calculations and could be easily implemented in real-life scenarios.

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Conventional carpet cloak structures have been utilized to conceal the objects located on a planar perfect electric conductor surface. We systematically investigate hiding arbitrarily shaped objects on a rough surface, as a more general and practical scenario. In addition, the required cloak is designed considering different boundary conditions for the surface beneath the object, despite the previous studies. To achieve an invisibility cloak, taking advantage of linear coordinate transformation, a simple homogeneous material is obtained to realize the cloak structure, facilitating the fabrication processes. Numerical simulations validate the performance of the proposed cloaking method. Therefore, the proposed structure is capable of cloaking in more general and complicated scenarios.